This invention relates to a fire retardant composition and method and, more particularly, to non-combustible particle and wafer boards and doors, being an improvement on my Canadian Application No. 505,878 now Patent No. 1,258,328 and corresponding U.S. Pat. No. 4,746,555.
The aforementioned patents made use of a composition consisting essentially of 30 to 75% by weight of an inert filler selected from perlite and vermiculite, 10 to 30% by weight of wood chips and 3 to 15% by weight of a binder which is a mixture of an alkali metal silicate and a curable phenolic resin, at least one of which was present in dry form. A critical factor of the invention in the above mentioned patents was the use of wood chips (as contrasted to fibers) to provide rigidity and screw holding power. I have now discovered that even superior results can be obtained by substituting glass fibers having a diameter of the order of 10-15 microns and lengths under approximately 1" (25 mm), preferably the longest lengths.
The present invention is applicable, as before, to cores for use in wooden doors, panels such as particle board and wafer board coated with a thin layer of the inventive composition, and like products.